Various types of water-repellent cosmetics are used for protecting the skin from water or sweat or for preventing makeup from getting disordered by water or sweat. For example, cosmetics for foundation, such as creams and lotions, and cosmetics for make-up usually contain silicone oil or silicone resin as a water-repellent component. The silicone oil or silicone resin is effective for water-repellency to some extent but does not have sufficient oil-repellency. Therefore, cosmetics containing these ingredients still tend to get disordered on the skin due to sebum.
Hence, attempts have been made in various fields to develop a compound which repels both water and oil. For example, JP-A-2-295912 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses that cosmetics containing fluorine-modified silicone compounds, such as trifluoropropylsilicone, exhibits excellent resistance to both water and sebum.
A water- and oil-repellent base to be used in cosmetics should satisfy all the requirements: (a) to have sufficient repellency against sweat and sebum, (b) to have excellent emulsion stability, (c) to withstand mechanical contact (for example, when pressed with a handkerchief or a tissue), and (d) to have a controlled viscosity to give a good feel on application.
However, the known fluorine-modified silicone compounds do not sufficiently fulfill these requirements. That is, they have poor emulsion stability due to poor compatibility with general cosmetic bases, they easily come away on contact with a handkerchief, a tissue, etc. due to poor affinity to the skin, and they have poor spreadability on application to the skin because of high viscosity.
It has therefore been demanded to develop a compound having excellent water- and oil-repellency which is stable when incorporated into cosmetics, causes no disorder of makeup while on the skin, and gives a satisfactory feel on use.